Conjunctival Flora in Diabetic and Nondiabetic Individuals

To evaluate the conjunctival bacterial flora in diabetic patients and nondiabetic subjects.

Fifty-three diabetic patients and 43 nondiabetic healthy individuals were included in the study. A specimen was taken from each participant for the study by rubbing a sterile cotton-tipped swab on the inferior palpebral conjunctiva of the right eye. Samples were incubated in blood agar, chocolate agar, eosin methylene-blue lactose sucrose agar and sabouraud 4% dextrose agar. Isolated microorganisms were identified using routine microbiological methods.

Rates for bacterial isolations were determined as 38.5% in diabetic patients and 34.9% in nondiabetic controls. Staphylococcus aureus was isolated in 30% of cases in the diabetic patient group, while 20% tested positive for Escherichia coli, 10% for coagulase-negative Staphylococcus, 10% for Klebsiella pneumoniae and 30% for multiple bacteria. In the non-diabetic group, 53.3% of patients were positive for Staphylococcus aureus while coagulase-negative Staphylococcus was isolated in 26.7%, Klebsiella pneumoniae in 6.7% and multiple bacteria in 13.3% of patients. Although there was no statistically significant difference in the number of isolated bacteria between the diabetic and nondiabetic groups, gram-negative bacterial colonization was significantly higher in diabetic patients (χ2=0.129, p=0.719 and χ2=5.60, p=0.018, respectively).

Gram-negative bacteria are more common in the conjunctival flora of diabetic patients. This should be considered by clinicians when treating ocular infections in diabetic patients.